Field of the Invention
The present invention relates to an apparatus for discriminating the species of unknown bacteria rapidly with high accuracy, using an optical scattering pattern, and more particularly, to an apparatus for acquiring an optical scattering pattern to which polarization interference has occurred, using a single polarizer and a single polarization controller, and discriminating a bacterial species using the optical scattering pattern.
Discussion of the Related Art
Bacteria are everywhere, such as in food, animals, and human beings. If a human is infected with bacteria, he or she may suffer from fever, sickness, blood poisoning, food poisoning, and the like. Among them, Escherichia coli is commonly found in the lower intestine of humans or animals and may be discharged out in excretion, or during slaughter of animals. Escherichia coli is generally normal in the colon. However, Escherichia coli may cause peritonitis, blood poisoning, and so on in parts other than the colon. Even in the colon, pathogenetic Escherichia coli may cause infectious diarrhea. Listeria grows well in fast food, dairy food, and meat and causes blood poisoning and meningitis. Its death rate reaches 20 to 25%. Salmonella grows well even at low temperature, and its main infection source is poultry and eggs. If a human is infected with salmonella, salmonella may cause typhoid with diarrhea, fever, or stomachache, coloenteritis, and the like.
These bacteria may adversely affect economy as well as health. If the number of bacteria in various foods, materials, and water exceeds a reference value, all of the items should be withdrawn, thus causing economic loss.
Therefore, bacterial detection and discrimination is significant for human health and economy.
Conventionally, an immune analysis scheme using an antibody, a DNA-based molecular biological scheme, a luminous principle-based analysis scheme, an electric resistance analysis scheme, an optical scattering pattern detection scheme, and so on are available for bacterial detection and discrimination.
Among them, the optical scattering pattern detection scheme uses an optical scattering pattern obtained by transmitting light from a laser diode through two linear polarizers and a bacterial colony in an open free space.
A shortcoming with the conventional optical scattering pattern detection scheme is that each time a new scattering pattern is to be acquired for the same bacterial colony, a test device should be reset because the laser diode is arranged in a light-shielding capturing unit.
Moreover, since light from the laser diode is immediately guided to the open free space, light is easily introduced from the outside in the conventional optical scattering pattern detection scheme. The resulting influence on a final detected scattering pattern makes it difficult to obtain a clear scattering pattern unique to the bacterial colony.